Currently the company operates a 1975 Leyland Double Decker. It recently has been having issues where the throttle will not function. So far every time a mechanic has been working on it, they have had to clear out foreign matter. It will work briefly and by the next day it is back to not operating again. The tank and regulator that feed the throttle are real slow to no air at all. What would be the main cause for this problem and how do we prevent it from reoccuring? Any information on this would be appreciated.

Neil, Is this an Atlantean? Is the air throttle original from the factory? I ask because my 1976 Daimler Fleetline has a hydraulic throttle (and it's also beginning to act up but that's another thing).

Yes both the Double Deckers are Atlanteans. However, both buses did not come with service records and originated from two different areas in The United States. So it is hard to say if it is the original throttle or rebuilt. The bus in question originated from a dry environment and here in Illinois are moisture level is higher. Currently the local mechanics are still flushing out foreign matter out of the air system. They did point out that the bus did not have an air dryer on the system. Did the Atlantean come equipped with an air dryer standard?
Thank you,
Neil Hoover

Hi Neil,
I don't have that problem since I have Bristol Lodekka but my bus does have air brakes and I had a similar problem with dirt in the brake actuators. Has your mechanic pulled off the air tanks and checked for rust on the inner surfaces? My tanks looked great from the outside but when I pulled off the lines and had them checked they were rusted from not being drained.
Most air tanks get moisture in them from the condensation during the compression of the air .The tanks have to be drained every day or two. I would bet some of the dirt is coming from the tanks. I had mine rebuilt then I put an in line air filter. I have not had problems since doing this. I blew out all the air lines all the way to the actuators.
How about joining the club? We have a service manual for the Atlantean in our Members Only section free to members.
And you would be joining the only club for British Bus Owners on this side of the big pond.
There are a lot of Atlantean buses coming across now and I think we have a few members with them.

Hello,
Thanks for making us aware about such kind of sensitive news. I am really very interested in aviation and i liked to read about articles and news related to that. I hope you will always keep on updating us with such kind of sensitive news.......!!!

The throttle is often supplied by the secondary or Aux tank.
To protect the main braking system a pressure regulator valve is installed on the SEC/Aux tank.
This valve opens at 75 psi and can be equated to a spring loaded door. Basically as long as there is 75 psi minimum in the main tank(s) the "door" will open allowing air to feed the sec/aux tank and power the throttle. Poorly adjusted pressure regulator valves can starve the system from reliable operation.
Now do be aware some UK Passenger Executives required additional safety infrastructures such as the doors must be closed before the bus can accelerate away. So system were never common but custom built to suit customers needs!

Yes sludge and contamination in poorly maintained buses can infiltrate the system and cause poor throttle response.
Dennis